Generalization of a model of tissue response to radiation based on the idea of functional subunits and binomial statistics†

2001 ◽  
Vol 46 (5) ◽  
pp. 1501-1518 ◽  
Author(s):  
P Stavrev ◽  
N Stavreva ◽  
A Niemierko ◽  
M Goitein
Author(s):  
R.F. Dodson ◽  
L.W-F Chu ◽  
N. Ishihara

The extent of damage surrounding an implanted electrode in the cerebral cortex is a question of significant importance with regard to attaining consistency and validity of physiological recordings. In order to determine the extent of such tissue changes, 150 micron diameter platinum electrodes were implanted in the cortex of four adult baboons, and after eight days the animals were sacrificed by whole body perfusion with a 3% glutaraldehyde in 0.1M phosphate fixative.The calvarium was carefully removed and the electrode tracts were readily discernible in the firm, glutaraldehyde fixed tissue.Careful dissection of the zone of the electrode tract resulted in a small block which was further sectioned into tip, mid-tract and surface areas. Ultrastructurally, damage extended from the electrode sheath to the greatest extent of from 0.2 to 3.5 mm.


Kidney Cancer ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 151-158
Author(s):  
Katherine Yuxi Tai ◽  
Jad M. El Abiad ◽  
Carol D. Morris ◽  
Mark Christopher Markowski ◽  
Adam S. Levin

BACKGROUND: Checkpoint inhibitors and receptor tyrosine kinase inhibitors (RTKIs) have changed the standard of care for metastatic renal cell carcinoma (mRCC). Anecdotal evidence suggests these therapies may be less effective for treating bone than soft-tissue metastases. PURPOSE: We performed a retrospective review evaluating the relative clinical responses in soft-tissue and bone metastases in patients undergoing therapy using RTKIs and anti-programmed death-1 (PD-1) agents for mRCC. METHODS: Of the 2,212 patients in our institutional cancer registry with renal cell carcinoma (1997–2017), 68 (82 disease courses) were identified with measurable bone and soft-tissue metastases treated with RTKIs and/or PD-1s. Extent of metastasis was quantified at the time of therapy initiation (baseline) and at 3 months, 6 months, and 1 year. Changes in disease status were categorized as complete response, partial response, stable, mixed, or progression of disease according to RECIST v1.1 and MD Anderson criteria. These categories were further organized into “response to treatment” or “evidence of progression” to generate a generalized linear effects model with soft-tissue response as the independent variable and bone response as the dependent variable. Alpha = 0.05. RESULTS: Soft-tissue response correlated with bone response at 3 months (76 disease courses, p = 0.005) and 6 months (48 disease courses, p = 0.017). Of the patients with controlled soft-tissue disease, only 14 (19%) and 15 (32%) had progression in bone at 3 and 6 months, respectively. CONCLUSION: Contrary to anecdotal reports, osseous metastases do not appear to respond worse than soft-tissue metastases to treatment with these agents.


2003 ◽  
Vol 774 ◽  
Author(s):  
Janice L. McKenzie ◽  
Michael C. Waid ◽  
Riyi Shi ◽  
Thomas J. Webster

AbstractCarbon nanofibers possess excellent conductivity properties, which may be beneficial in the design of more effective neural prostheses, however, limited evidence on their cytocompatibility properties exists. The objective of the present in vitro study was to determine cytocompatibility and material properties of formulations containing carbon nanofibers to predict the gliotic scar tissue response. Poly-carbonate urethane was combined with carbon nanofibers in varying weight percentages to provide a supportive matrix with beneficial bulk electrical and mechanical properties. The substrates were tested for mechanical properties and conductivity. Astrocytes (glial scar tissue-forming cells) were seeded onto the substrates for adhesion. Results provided the first evidence that astrocytes preferentially adhered to the composite material that contained the lowest weight percentage of carbon nanofibers. Positive interactions with neurons, and, at the same time, limited astrocyte functions leading to decreased gliotic scar tissue formation are essential for increased neuronal implant efficacy.


2021 ◽  
Vol 9 (6) ◽  
Author(s):  
Toshiaki Kawano ◽  
Takashi Hirano ◽  
Maki Fujinaga ◽  
Yoshinori Kadowaki ◽  
Takayuki Matsunaga ◽  
...  

Biotribology ◽  
2021 ◽  
Vol 26 ◽  
pp. 100163
Author(s):  
Songyun Liu ◽  
Deborah J. Hall ◽  
Craig J. Della Valle ◽  
Michael J. Walsh ◽  
Joshua J. Jacobs ◽  
...  

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Tim Lenz-Habijan ◽  
Pervinder Bhogal ◽  
Catrin Bannewitz ◽  
Ralf Hannes ◽  
Hermann Monstadt ◽  
...  

Abstract Background Flow diverters (FDs) are widely used in the treatment of intracranial aneurysms, but the required medication increases the risk of haemorrhagic complications and limits their use in the acute setting. Surface modified FDs may limit the need for dual antiplatelet therapy (DAPT). Hydrophilic polymer coating (HPC) may reduce the need of medication. Methods This explorative study, approved by the local authorities and the local welfare committee, compared stent behaviour and overall tissue response between HPC-coated FDs and uncoated FDs, both implanted into the common carotid arteries of eight New Zealand white rabbits. Endothelialisation, inflammatory response, and performance during implantation were assessed. Angiographic follow-up was performed to observe the patency of the devices after implantation and after 30 days. Histological examinations were performed at 30 days to assess foreign body reaction and endothelialisation. Kruskal-Wallis and Wilcoxon tests were used to compare non-parametric variables. Results Angiography showed that both coated and uncoated FDs performed well during implantation. All devices remained patent during immediate follow-up and after 30 days. Histopathology showed no significant difference in inflammation within the vessel wall between the two cohorts (2.12 ± 0.75 vs. 1.96 ± 0.79, p = 0.7072). Complete endothelialisation of the stent struts was seen with very similar (0.04 ± 0.02 mm vs. 0.04 ± 0.03 mm, p = 0.892) neoendothelial thickness between the two cohorts after 30 days. Conclusion Taking into account the limitation in sample size, non-significant differences between the HPC-coated and uncoated FDs regarding implantation, foreign body response, and endothelialisation were found.


2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Irina A. Shurygina ◽  
Мichael G. Shurygin ◽  
Lubov V. Rodionova ◽  
Nataliya I. Ayushinova

AbstractObjectivesTo study the expression of growth factors in the regulation of tissue repair after peritoneal damage tissue response to peritoneal damage.MethodsExperimental study in 35 male Wistar rats determining the evolution over time of the tissue response to aseptic peritoneal damage. A standardized bowel and peritoneal lesions were created in the right lower quadrant by laparotomy. Then, tissular expression of growth factors was evaluated by multiplex polymerase chain reaction at seven timepoints between 6 h and 30 days, postoperatively.ResultsTissular responses of granulocyte-stimulating factors (Csf2, Csf3), connective tissue growth factor (Ctgf), epidermal growth factors and receptor (Egf, Egfr), fibroblast growth factors (Fgf2, 7 and 10), heparin binding EGF-like growth factor (Hbegf), hepatocyte growth factor (Hgf), insulin-like growth factor-1 (Igf1), mitogenic transforming growth factors (Tgfa, Tgfb1, Tgfbr3), and vascular endothelial growth factor A (Vegfa) were biphasic with a first expression peak at day 3, followed by a more pronounced peak at day 14.ConclusionsWe observed a long-lasting, widespread response of tissular growth factors for at least two weeks after peritoneal damage. To be clinically effective, the prophylaxis of postoperative adhesions might be needed for an extended period of time.


Antioxidants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 735
Author(s):  
Greg Hutchings ◽  
Łukasz Kruszyna ◽  
Mariusz J. Nawrocki ◽  
Ewa Strauss ◽  
Rut Bryl ◽  
...  

Currently, atherosclerosis, which affects the vascular bed of all vital organs and tissues, is considered as a leading cause of death. Most commonly, atherosclerosis involves coronary and peripheral arteries, which results in acute (e.g., myocardial infarction, lower extremities ischemia) or chronic (persistent ischemia leading to severe heart failure) consequences. All of them have a marked unfavorable impact on the quality of life and are associated with increased mortality and morbidity in human populations. Lower extremity artery disease (LEAD, also defined as peripheral artery disease, PAD) refers to atherosclerotic occlusive disease of the lower extremities, where partial or complete obstruction of peripheral arteries is observed. Decreased perfusion can result in ischemic pain, non-healing wounds, and ischemic ulcers, and significantly reduce the quality of life. However, the progressive atherosclerotic changes cause stimulation of tissue response processes, like vessel wall remodeling and neovascularization. These mechanisms of adapting the vascular network to pathological conditions seem to play a key role in reducing the impact of the changes limiting the flow of blood. Neovascularization as a response to ischemia induces sprouting and expansion of the endothelium to repair and grow the vessels of the circulatory system. Neovascularization consists of three different biological processes: vasculogenesis, angiogenesis, and arteriogenesis. Both molecular and environmental factors that may affect the process of development and growth of blood vessels were analyzed. Particular attention was paid to the changes taking place during LEAD. It is important to consider the molecular mechanisms underpinning vessel growth. These mechanisms will also be examined in the context of diseases commonly affecting blood vessel function, or those treatable in part by manipulation of angiogenesis. Furthermore, it may be possible to induce the process of blood vessel development and growth to treat peripheral vascular disease and wound healing. Reactive oxygen species (ROS) play an important role in regulation of essential cellular signaling pathways such as cell differentiation, proliferation, migration and apoptosis. With regard to the repair processes taking place during diseases such as LEAD, prospective therapeutic methods have been described that could significantly improve the treatment of vessel diseases in the future. Summarizing, regenerative medicine holds the potential to transform the therapeutic methods in heart and vessel diseases treatment.


Sign in / Sign up

Export Citation Format

Share Document